Process for cracking petroleum oil



menait Feb. 7, 192s.

UNITEDl STATES A 1,658,415 PATENT OFFICE.

i ROBERT T. Pontoon, or BOSTON, MASSACHUSETTS, AssIoNOR Toumvnasaz. OIL

PRODUCTS oomramr, or onIcAGO, ILLINOIS, a CORPORATION or SOUTH DAKOTA.

., PROCESS FOR` CRACKING- PETROLEUM OIL.

` Application nled December 20,1990. Serial No. 431,838.

This invention relates to improvements in process and for crackingpetroleum oil and refers more particularly to that type .of

process in which the generated vapors are subjected to reflux condensingaction and the reiiux condensate, i. e., the incompletely converted Oilconstitutents subjected to further cracking reaction.

With certain types of petroleum oil, the

reflux condensate produced inthe cracking operation is more desirablysubjected to further cracking reaction under different temperatures andpresures than is the original oil. By means of the present process, thisrefiux condensate 'caribe separately cracked as part of a continuousprocess and under different. conditions of temperature and pressure thanthe raw oil. As a further feature of the invention, the generated vaporsare 2 subjected to a4 double 'refi'ux condensing action in which theheaviest portions of the vapors are condensed and separately recrackedwhile thev intermediate portion of the vapors, i. e., those lighter thanthe heaviest but not yet suiciently cracked and therefore heavier thanthe lightest, are separately condensed, subjected to further crackingunder still different conditions ot temperature and-pressure.

In the drawing, the single figure shows a somewhat diagrammatic viewpartly in side elevation and 'partly .in vertical section of improvedapparatus for carrying out my process.

Referring in detail to the drawing, A. B andv C designate three separatefurnaces. In the furnace A is mounted a heatingcoil 1, as for example. acontinuous coil of 2 to 6" pipe. This coil is fed from the charging pump2, connected to the raw oil supplv by inlet line 3 and delivering theraw oil to the heatingelement through the feed line 4 having throttlevalve 5. The discharge side of the coil is connected by transfer line 6having throttle valve 7 to vapor chamber 8. This vapor chamber 8 isprovided with liquid residue drawoff pipe 9 controlled by throttle valve10.' It also has vapor 'outlet pipe 11 and downwardly inclined extensionpipe 11 having throttle valve 12 and con'- nected to the lower side ofthe dephlegmator' 13'. The upper end of the dephlegmator 13 is connectedby vapor pipe 14 having throttle valve 15 to a partial condenser orreflux condenser 16. The vapor space of this condenser is connected by apipe 17 -having throttle valve 18 to iinal condenser coil 19 seated inwater condenser 20. The \lower end of the coil 19 is connected to theupper part of receiver 21. This receiver 21 has li uid level gauge 22.liquid drawotf pipe 23, avin throttle valve 24 and gas outlet pipe 25,avingthrottle valve 26. v Referring back to the dephlegmator 13, to itslower end is connected a reflux condensate pipe 27, which leads to theinlet side of the heating coil 28 mounted in the furnace C. A throttlevalve 29 is interposed in the line 27. There is likewise interposed inthis line a pump 30 provided at either side with valves 31 and 32,whereby the refiux condensate may be pumped under increased pressure, ifdesired. A by-pass line 33 having athrottle valve 34 is provided for bvpassing the pump, if desired. The discharge side of the coil 28 isconnected by transfer line 35 havin throttle valve 36 to vapor chamber37. his vapor chamber 37 4is provided with liquid drawoif pipe 38controlled by throttle valve 39. The upper end of the vapor chamber isconnected by vapor pipe 40 and downwardly inclined pipe 41 havingthrottle valve 42, to the lower side of a ,dephlegmator 43.

is provided with vapor Outlet pipe 44 having throttle valve .45, whichpipe 44 is connected to final condenser coil 46 seated in condenser box47. The lower end of the coil is connected by pipe 48 having throttlevalve 49 to the upper part of receiver 50. This receiver 50 has liquiddrawoff pipe 51 con- This dephlegmator 43 trolled by throttle valve 52and gas outlet y pipe 53 controlled by throttle valve 54.

Referringl back to the dephleginator 43, to its lower end is connectedreiux return pipe 55 in which is interposed a pump 56 having at eitherside valves 57 and 58. The pump may be by-passed by pipe 59 having valve60. This line 55 connects to extension 55 leading to the heating coil 61seated in furnace B. This coil may be of the same construction as theother two. The .discharge side of this coil is connected by transferline 63 having throttle valve 64 to an expansion or vapor chamber 65.This eX- pansion chamber l65 has a liquid drawoi ipe 66 controlled bythrottle valve 67. It 1s also provided with the vapor outlet pipe valve97 interposed in the end of the pipev The upper end of the dephlegmatoris con nected by vapor pipe 72 having throttle valve 73 to condensercoil V74 seated in condenser box 75. The lower end of the coil isconnected by pipe 76 having throttle valve 77 to the top of -receiver78. This receiver 78 has vliquid drawof'f pipe 79 controlled by throttlevalve 80 and gas outlet throttle valve 82.

The lower end of the dephlegmator 71 1s connected by reflux condensatep1pe 83 having throttle valve 84 to a second return pipe 85 leading backto the pipe 55', whereby 1t may be returned to the heating coil 61. 'l`he line 83 is also provided with the branch plpe 86 having throttlevalve 87 connected to any suitable receptacle (not shown), whereby thereflux condensate may be led elsewhere than delivered to the coil 61. Inthis case a. valve 88 in the line 85 can be closed and valves 84 and 87regulated. 1n the pi e 85 1s interposed a pump 89 having at e1t er side,valves 90 and 91, whereby the reflux condensate may be returned to thepipe 55 under pressure. This pump may be by-passed by means of pipe 81controlled by the pipe 92 having throttle valve 93. A

throttle valve 94 is interposed in the pipe 55.l l have heretoforestated that the rellux condensate from the pipe 55 may be de' livered tothe pipe 55,. It also may be delivered elsewhere, to-wit:-to a suitablereceptacle, (not shown), by means of branch 95 having throttle valve 96.In this case the 55 will be closed. y

Referring back to the partial condenser 16,

to its lower side is 'connected condensate return pipe 98. In this pipeline 98 is ,interposed a pump 99 having suitable valves at either sidethereof and `Aalso provided with the by-pass line 100 having valve 101.`The lower end of the pi e 98 is connected as shown at 102 to the line55', provided with control valve 103. The reflux condensate instead ofbeing returned to the pipe 55 may be delivered to a suitable receptacle(not shown) by means ofthe branch 104 having throttle valve 105.V

The process may be operated as follows: Raw oil, as for example,petroleum -fuel oil, may be fed continuously to the heating tubes 1where it is heated to a temperature of say, 750 degrees F. and while linsubstantially liquid phase passed to the vapor chamber 8 and thence tothe first reflux condenser. The uncondensed portions will pass to thepartial condenser 16 and the still uncondensed ortions will pass to thecondenser 19 and thence to the receiver 21. All of the elements so farreferred to may be maintained under a pressure of say, 150 pounds. Thereflux condensate from the dephlegmator 13 may be astenia pumped bymeans of the pump 30 to the second heating coil 28 and there subjectedto a temperature 'of say, 800 degrees F., passingthence -to the vaporchamber and thence to the dephle ator 43.. The uncondensed the top ofreceiver 50. This part of the sy'stem from the coil 28 to receiver 50may be means of the pump 56 to the lines 55 and 55 and thence to theheating coils 61 seated in the furnace B. Here the reflux condensatewill be heated to a temperatureyof say, 850 degrees F. The refluxcondensate will thence pass into the chamber 65 and the vapors therefrominto the dephlegmator 7.1. The uncondensed portions will pass out of thedephlegmator into the condenser 74 and thence to the receiver 78. Theheating tubes 61 and associated mechanism may be maintained under apressure of say, 250 pounds. The reflux condensate from the dephlegmator71 may be returned by pump 89 to the pipe 55 and thence through thetubes 61.

vThe reflux condensate fromthe second re`i 70.*'. 'portions wil passout'mofY the top of the dephlegmator 43 into the coil 46 and thence toyit will be seen that the raw oil and the diii'erent cuts of refluxcondensate are all treated under different pressures and temperatures.

The process may be carried out exactly in' the manner above describedexcept that the reflux condensate from the artial condenser 16 may beby-passed throug the line 104 or the reflux condensate from thedephlegmator 71 may be by-passed through the line 86 and may berecracked in a system separate if desired, or the partial condenser maybe left in the system in the manner as described and only the refluxcondensate from the dephlegmator 71 drawn ofl through the line 86.

The process may be operated in the manner rst above described, exceptthatthe oil 'in the rst heating coil may be heated to a temperature ofsay, 650 degrees F. and Sub' '-jected to a pressure of 100 pounds; theoil in the second heating coil, to-wit, in the furnace C heated to atemperature of 750 degrees F. and subjected to a pressure of 150 poundswhile the reflux condensate passed through the furnace B may be heatedto a temperature of 750 degrees F. and subjected to a pressure of 200pounds.-

The process may also be operated by maintaining a pressure of say, 150poundsl on the heating coil 1; a reduced pressure, as for example, 75pounds, on its associated condenser and dephlegmator and partialcondenser and 50 pounds on the final condenser 19 and receiver 21, theoil being' heated to a temperature of say, 680 degrees F. The pressureico on the oil in the heating coil in the furnace C may be 200 pounds,at a temperature of 720 degrees F.; the pressure on the associated vaporchamber and final condenser and receiver reduced say, to pounds. The oilin the heatin coil 61 may be heated to a temperature of degrees F.,subjected to a pressure of 250 pounds, while the associated vaporchamber and dephlegmator may be maintained under a ressure of say, 100pounds and the associated iinal condenser and receiver at 50 pounds.

The process may also be carried out in the manner last described exceptthat the vapor chamber may be maintained under the same pressure as theoil in the heating tubes While the dephlegmator may be maintained atatmospheric pressure.

I claim as my invention:

l. A process of cracking oil, which con- M sists in passing the oilthrough a heating coil wherein it is subj ected to crackin(Sr conditionsof heat and pressure, in discharging the oil from said coil into a vaporchamber, in passing the vapors from said vapor chamber throughsuccessive dephlegmators, in passing the reflux condensate from each ofsaid dephlegmators under applied pressure to independent heating zonesand in subjecting the reflux condensate passed to each of saidindependent heating zones to higher temperatures than the tem eraturesto which the oil is subjected in said heating coil.

2.' A process of cracking oil, which consists in passing the oil througha heating zone wherein it is subjected to cracking conditions of heatand pressure, in dephlegmating the vapors produced from said heatingzone in successive dephlegmators, in passing the reflux condensate fromeach of said dephlegmators under an applied pressure to independentheating zones in subjecting the reflux condensate in each of saidindependent heating zones to a higher temperature than that to which theoil is subjected in said rst named heating zone, in condensing thevapors issuing from the last of said dephlegrnators, and in collectingthe resulting distillate.

3. A continuous process for cracking hydrocarbon oil, consisting ininitiall subjecting the oil to cracking conditions o heat and pressureto cause substantial conversion thereof, in subjecting the vaporsevolved `from the oil to primary and secondary dephlegmatin actions, inseparately subjecting the re uxcondensates resulting from said primaryand secondar dephlegmating actions to independent crac ing reactions attemperatures substantially above the temperature to which the oil wasinitially subjected.

ROBERT T. PoLLocK.

